<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .a{
      width: 600px;
      background-color: aqua;
      position:fixed;
      bottom: 0;
    }

    .o:hover{
      top: -66px;
      transition: top 1s ease-in-out ;
    }

    .p{
      width: 500px;
      height: 20px;
      background-color: brown;
      margin: 0 auto;
    }

    .o{
      width: 500px;
      height: 70px;
      background-color: blue;
      position: absolute;
      top: -23px;
    }
  </style>
</head>
<body>
  
  <div class="a">
  <div class="o">
    <div class="p"></div>
  </div>
</div>
</body>
</html>